Your car exhaust is the metal pipe that juts out from underneath the back of your car. In fact, what you can see is the tailpipe, the exhaust system runs under the entire length of the car's body into the engine.

What Your Exhaust Actually Does

When operating, the internal combustion engine produces six gases, three of which, carbon monoxide, nitrogen oxide and nitrogen monoxide, are highly toxic. The exhaust gets rid of these gases and keeps them away from the interior of the vehicle and passengers. Disposing of poisonous fumes is just one function of the exhaust. The others are:

  • To reduce and control noise produced by the engine;
  • Improve the performance of the engine; and
  • Reduce fuel consumption.

Cars come with standard exhausts fitted by the vehicle's manufacturer. Drivers seeking to improve the efficiency of their car and increase its power often fit aftermarket exhaust systems which are build to a higher specification that standard exhausts, with those specific aims in mind. Exhaust systems can be custom-built for any car.

Components in an Exhaust System

An exhaust includes:

  • A manifold
  • Turbocharger
  • Catalytic Converter
  • A Silencer or muffler

The manifold is usually a steel tube with a connection for each of the exhaust ports in the. The gases pass through the separate ports on the manifold through a flange into the front pipe of the exhaust, then through a turbocharger which increase engine power if one is fitted, along the pipe into the catalytic converter where the toxic fumes are changed into inert gas and through the silencer to the tailpipe from which they are emitted. The whole system is attached to the bottom of the car using a variety of clamps, gaskets, flanges and nuts and bolts. Other components of an efficient exhaust system include a heat shield that runs between the system and the floor, particularly around the catalytic converter, which is where the system reaches its hottest point. There are also sensors for fuel management; one close to the manifold and the other along the pipe between the catalytic converter and the silencer. These sensors feed information back to the car's control system.

How an Exhaust Can Improve Your Car

Replacing the exhaust manifold can reduce both back pressure and heat build up in the engine. A cooler manifold increases engine power and less heat in the engine helps protect heat-sensitive parts and prolongs their life. Spraying an exhaust with ceramic coating also helps to reduce the amount of heat lost and back pressure and in so doing extends the life of the exhaust. those car owners who invest in performance exhausts see a serious improvement in their car's performance.

Different Systems

A car can have a single or dual system. A single system has one set of components; a dual system two sets. So, two manifolds, turbochargers, catalytic converters, silencers and tail pipes. In a dual system there can be an imbalance in performance with one of the systems producing less power. That problem can be rectified by a crossover system where gases can flow freely between the pipes of both systems. Performance exhausts are also available for cars used for racing.

Three Ways to Customise an Exhaust System


Components in the system are replaced from the catalytic converter back, including the silencer and tailpipe. This is the most popular customisation and it is cheaper than the header-back option. The adaptation frees-up gas flow, increases engine power and reduces fuel usage, although the extent to which it does those things depends on effectiveness of the rest of the system. Because the standard catalytic converter remains in place, emissions should meet the legal requirement.


A header-back replaces the system from the manifold to the tailpipe. This is an expensive customisation and it can be a difficult job. Aftermarket header-back systems are designed and built differently to standard exhausts. The pipes have a larger diameter which facilitates better flow and bends are created, not through crush bending as in manufacturer-fitted components but through mandrel bending which eliminates restrictive kinks. The benefits of a header-back system include increase in horsepower and more effective running of the engine.


All components from the rear axle to the tip of the tailpipe are replaced. This is the least expensive option and the easiest to fit. It does bring benefits that trump the standard exhaust, particularly in terms of power gains.

Exhaust Problems

To make sure your car is performing efficiently and within legal standards, it is important to pay attention to the health of your exhaust system. You should check regularly for rust and corrosion and make an inspection should you hear any rattling as some components holding the pipes in place may have come loose. If, your engine is making more noise than usual or there has been a change in the colour of your exhaust fumes, you must investigate immediately.





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